This color contains the following pigments:

PO20—Cadmium Orange

Pigment Type

cadmium

Chemical Name

cadmium sulfide and cadmium selenide

Chemical Formula

CdS × CdSe

Properties

Cadmium Orange was the first true orange and was made by mixing Cadmium Yellow with Cadmium Red. It is a pure hue with excellent opacity and low toxicity compared with its predecessors. It also has very high hiding power. The greatest tinting strengths are possessed by the deeper shades. Only the highest grades contain pure Cadmium Orange without barium mixed in it. Cadmium pigments have been partially replaced by azo pigments, which are similar in lightfasness to the cadmium colors, cheaper, and non-toxic.

Permanence

Cadmium Orange has excellent permanence, but like many cadmium pigments, it will fade in fresco or mural painting. The deeper varieties of this pigment are the most permanent. The paler varieties have been known to fade when exposed to sunlight.

Toxicity

Cadmium Orange is a known human carcinogen. It is extremely toxic if inhaled and slightly toxic if ingested.

History

Cadmiums get their names from the Latin word cadmia, meaning zinc ore calamine, and the Greek word kadmeia, meaning Cadmean earth, first found near Thebes, the city founded by the Phoenician prince Cadmus. Metallic cadmium was discovered in 1817 by Friedrich Strohmeyer. It was used sparingly after its discovery due to the scarcity of cadmium metal.

Alternate Names

PY35—Cadmium Yellow

Pigment Type

inorganic, cadmium

Chemical Name

cadmium zinc sulfide

Chemical Formula

CdZnS

Properties

Cadmium Yellow is brilliant, dense, and opaque, with good tinting strength and very high hiding power. It is the artist’s principal bright yellow and is available in light, medium, and dark shades. The deeper shades appear deep orange and have the greatest tinting strength. It is slow-drying in oil form and is used in both oil and watercolor form. It cannot be mixed with copper-based pigments. A clean Cadmium Orange is created when Cadmium Yellow is mixed with Cadmium Red. Hues vary by brand. Cadmium pigments have been partially replaced by azo pigments, which are similar in lightfastness to the cadmium colors, cheaper, and non-toxic.

Cadmium Yellow is usually available in a pure grade, or in a cadmium-barium mix. This mix has the same permanence with a lower tinting strength.

Permanence

Cadmium Yellow is lightfast and permanent in most forms, but like most cadmium colors, it will fade in fresco or mural painting. The deeper shades are the most permanent. The pale varieties have been known to fade with exposure to sunlight in conditions where moisture is able to penetrate the binder.

Toxicity

Cadmium Yellow is a known human carcinogen. It can be hazardous if chronically inhaled or ingested.

History

Cadmiums get their names from the Latin word cadmia meaning zinc ore calamine, and the Greek word kadmeia, meaning Cadmean earth, first found near Thebes, the city founded by the Phoenician prince Cadmus. Metallic cadmium was discovered in 1817 by Friedrich Strohmeyer. Oil colors were first made from Cadmium Yellow pigments in 1819, replacing toxic Chrome (lead) Yellows. However, their production was delayed until 1840 due to the scarcity of cadmium metals. Landscape painters, such as Claude Monet, preferred Cadmium Yellow to the less expensive Chrome Yellow because of its higher chroma and greater purity of color.

PW1—Barium Sulfate

Pigment Type

Chemical Name

Chemical Formula

Properties

Barium Sulfate is a low tinting strength neutral white, often used as an extender.

Permanence

Barium Sulfate has excellent lightfastness.

Toxicity

Although barium is a heavy metal and is toxic, barium sulfate has very low solubility in water, and is not easily absorbed biologically. Barium sulfate is used as a contrast medium in radiology.

History

Barium sulfate is the principle component of baryte, a common mineral. It has many industrial uses. John Dalton's discovery (1803) of a process to reduce barium sulfate to barium sulfide was instrumental in the development of the theory of atoms.

Alternate Names

PB15:3—Phthalo Blue

Pigment Type

organic

Chemical Name

beta copper phthalocyanine

Chemical Formula

C32H16CuN8

Properties

Phthalo Blue PB15:3 is a structural variant of Phthalo Blue PB15 that produces more greenish tones.

Permanence

Phthalo Blues are completely lightfast and stable and are permanent for all paint uses. They are currently used in inks, coatings, and many plastics due to their stability and are considered a standard pigment in printing ink and the packaging industry.

Toxicity

Phthalo Blues have no significant hazards, although those made before 1982 contained some PCBs (polychlorinated biphenyls).

History

Developed by chemists using the trade name Monastral Blue, the organic blue dyestuff now known as Phthalo Blue was presented as a pigment in November 1935 in London. Its discovery was accidental. The dark color was observed in a kettle where a dye was being made from a British dyestuff plant. The demand for such a pigment came from commercial printers who wanted a cyan to replace Prussian Blue.